Add some tests for associated type normalization edge cases

tests/ui/privacy/projections.rs

@@ -0,0 +1,60 @@
+mod m {
+ struct Priv;
+ pub type Leak = Priv; //~ WARN: `Priv` is more private than the item `Leak`
+}
+
+trait Trait {
+ type A<T>;
+}
+
+impl Trait for u8 {
+ type A<T> = u8;
+}
+
+fn check() -> <u8 as Trait>::A<m::Leak> {
+ //~^ ERROR: `Priv` is private
+ 0
+}
+
+trait Trait2 {
+ type A<T>;
+}
+
+impl Trait2 for u8 {
+ type A<T> = m::Leak;
+ //~^ ERROR: `Priv` is private
+ //~| ERROR: private type `Priv` in public interface
+}
+
+fn check2() -> <u8 as Trait2>::A<u32> {
+ //~^ ERROR: `Priv` is private
+ todo!()
+}
+
+trait Trait3 {
+ type A<T: Trait>;
+}
+
+impl Trait3 for u8 {
+ type A<T: Trait> = T::A<m::Leak>;
+ //~^ ERROR: `Priv` is private
+ //~| ERROR: private type `Priv` in public interface
+}
+
+fn check3() -> <u8 as Trait3>::A<u8> {
+ todo!()
+}
+
+trait Trait4 {
+ type A<T: Trait3>;
+}
+
+impl Trait4 for u8 {
+ type A<T: Trait3> = T::A<u8>;
+}
+
+fn check4() -> <u8 as Trait4>::A<u8> {
+ todo!()
+}
+
+fn main() {}

tests/ui/privacy/projections.stderr

@@ -0,0 +1,62 @@
+warning: type `Priv` is more private than the item `Leak`
+ --> $DIR/projections.rs:3:5
+ |
+LL | pub type Leak = Priv;
+ | ^^^^^^^^^^^^^ type alias `Leak` is reachable at visibility `pub(crate)`
+ |
+note: but type `Priv` is only usable at visibility `pub(self)`
+ --> $DIR/projections.rs:2:5
+ |
+LL | struct Priv;
+ | ^^^^^^^^^^^
+ = note: `#[warn(private_interfaces)]` on by default
+
+error[E0446]: private type `Priv` in public interface
+ --> $DIR/projections.rs:24:5
+ |
+LL | struct Priv;
+ | ----------- `Priv` declared as private
+...
+LL | type A<T> = m::Leak;
+ | ^^^^^^^^^ can't leak private type
+
+error[E0446]: private type `Priv` in public interface
+ --> $DIR/projections.rs:39:5
+ |
+LL | struct Priv;
+ | ----------- `Priv` declared as private
+...
+LL | type A<T: Trait> = T::A<m::Leak>;
+ | ^^^^^^^^^^^^^^^^ can't leak private type
+
+error: type `Priv` is private
+ --> $DIR/projections.rs:14:15
+ |
+LL | fn check() -> <u8 as Trait>::A<m::Leak> {
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^ private type
+
+error: type `Priv` is private
+ --> $DIR/projections.rs:29:39
+ |
+LL | fn check2() -> <u8 as Trait2>::A<u32> {
+ | _______________________________________^
+LL | |
+LL | | todo!()
+LL | | }
+ | |_^ private type
+
+error: type `Priv` is private
+ --> $DIR/projections.rs:24:17
+ |
+LL | type A<T> = m::Leak;
+ | ^^^^^^^ private type
+
+error: type `Priv` is private
+ --> $DIR/projections.rs:39:24
+ |
+LL | type A<T: Trait> = T::A<m::Leak>;
+ | ^^^^^^^^^^^^^ private type
+
+error: aborting due to 6 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0446`.

tests/ui/privacy/projections2.rs

@@ -0,0 +1,38 @@
+mod m {
+ use super::*;
+ struct Priv;
+ pub type Leak = Priv; //~ WARN: `Priv` is more private than the item `Leak`
+
+ trait Trait3 {
+ type A<T: Trait>;
+ }
+
+ impl Trait3 for u8 {
+ type A<T: Trait> = T::A<Leak>;
+ }
+
+ pub trait Trait4 {
+ type A<T: Trait>;
+ }
+
+ impl Trait4 for u8 {
+ type A<T: Trait> = <u8 as Trait3>::A<T>;
+ //~^ ERROR: private associated type `Trait3::A` in public interface
+ //~| ERROR: private trait `Trait3` in public interface
+ }
+}
+
+pub trait Trait {
+ type A<T>;
+}
+
+impl Trait for u8 {
+ type A<T> = u8;
+}
+use m::*;
+
+fn check4() -> <u8 as Trait4>::A<u8> {
+ todo!()
+}
+
+fn main() {}

tests/ui/privacy/projections2.stderr

@@ -0,0 +1,34 @@
+warning: type `Priv` is more private than the item `Leak`
+ --> $DIR/projections2.rs:4:5
+ |
+LL | pub type Leak = Priv;
+ | ^^^^^^^^^^^^^ type alias `Leak` is reachable at visibility `pub(crate)`
+ |
+note: but type `Priv` is only usable at visibility `pub(self)`
+ --> $DIR/projections2.rs:3:5
+ |
+LL | struct Priv;
+ | ^^^^^^^^^^^
+ = note: `#[warn(private_interfaces)]` on by default
+
+error[E0446]: private associated type `Trait3::A` in public interface
+ --> $DIR/projections2.rs:19:9
+ |
+LL | type A<T: Trait>;
+ | ---------------- `Trait3::A` declared as private
+...
+LL | type A<T: Trait> = <u8 as Trait3>::A<T>;
+ | ^^^^^^^^^^^^^^^^ can't leak private associated type
+
+error[E0446]: private trait `Trait3` in public interface
+ --> $DIR/projections2.rs:19:9
+ |
+LL | trait Trait3 {
+ | ------------ `Trait3` declared as private
+...
+LL | type A<T: Trait> = <u8 as Trait3>::A<T>;
+ | ^^^^^^^^^^^^^^^^ can't leak private trait
+
+error: aborting due to 2 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0446`.